Machine for grinding balls.



J. G. IRWIN.

MACHINE FOR GRINDING BALLS.

APPLICATION FILED DEO.19, 1911.

Patented Oct. 29, 1912.

7 [III "To all whoniji maylcom emr I "1 Be it .known that I, JosnPH'G. IRWIN, a

thereto.

ed slidably on the bed 6, and adapted to be truly spherical and therefore become unre- -journaled in its bearings 13, in a manner JOSEPH G. IRWIN, 0011A, OKLAHOMAQ mcnmn Eon GRINDING Bans.

citizen of the United States, residing at. Oklahoma city, in the county of Oklahoma and State of Oklahoma, have invented cer tainnew and useful Improvements in Ma-, chines for Grinding Balls, of.which the following is a full, clear, and exact description, reference beinghad to the accompanying drawings.

Spherical bodies, such, for instance, as pool and billiard balls often shrink evenly or become .worn, so that they arenot liable for gaming purposes.

An object, therefore, of this invention is to automatically regrind partially spherical bodies to a substantially perfectly spherical sha e. 1

'O ther objects and advantages of the invention will become apparent from the ensuing description.

Referring to the drawings :Figu1'e 1 is a side elevation of an improved machine. Fig. 2 is an enlarged elevation view in the same direction as Fig. 1, showing chuck portions or grinding dies ofa machine with a ball between them for grinding. Fig. 3 is a similar view, partly in section, show-' ing the position assumed by the chucks or grinding dies when the grinding of the ball is finished. Fig. 4 is a face view of one of the grinding dies, taken in the direction of the axis line thereof. Fig. 5 is a similar view of the same die with parts added Referring to the several figures, in all of which like characters of reference designate like parts, the machine shown comprises, in part, a bed portion 6, with a common headblock 7 mounted thereon. The head-block 7 has a lathe spindle or arbor 8 journaled in its bearings 9, this spindle being provided with belt pulleys for driving it. In add)? tion to -the head-block 7 a tail-block 11, similar in shape to the head-block, is mountmoved to or from the head-block. In place of being provided with the usual tail-screw, the tail-block 11 has a spindle or arbor 12 similar to that of the head-block 7. In the further arrangement of the machine,- each of the spindles 8 and 12 is provided with a grinding die 14, shaped like the usual face- Specification of Letters Patent. Application-filed December 19, 1911. Serial No; 666,648.

plate of a lathe, the die of one spindle facing Patented Oct. 29,1912.

that of the other. Each of the dies 14 has truly sphericaldepression 15 hits face, so that when said dies are brought into contact l the two depressions form a truly spherlcal' interior space whose center is on the line of axis of the spindles'8 and 12."

In order that the slidable tail-block 11 may be yieldably forced toward the head-block '7 for purposes later shown, said tail-block and head-block are attached together by a tension spring 16. 7

In the use of this machine, the ball 17 to be ground isplaced between the dies 14, as shown in Fig.2, and projects into the depressions 15 thereof, the radius of curvature of said depressions being slightly shorter than th of the ball 17 so that, in fact, said dies willbe held a little way apart as shown 1 n said figure. The-dies 14 are then rotated in opposite directions, by causing the shafts t3 and 12 to be rotated in opposed directions in the'usual manner, causing the inner surfaceof the depressions 15 to grind the ball 17 down in size untilthe faces 18 of said dies contact each otherin the position shown in Fig. 3. This insures that the ball 17 will automatically be'ground to a substantially truly spherical form, and that the grinding process'will. cease at exactly the right instant.

To facilitate the grinding, a small quantity of any grinding substance, such as flower of emery, may be placed in the two depressions 15 before depositing the ball 17 therein. Thedepression of each die is provided with a number of radial outlet ducts 19 through which escapes the surplus *material resulting from the grinding, which must be eliminated during the process of grinding, in order, not only to facilitate the grinding operation, by allowing the grinding elements to do their work, but also to allow the removal of all substances that would otherwise prevent a complete contact between the walls of the depressions and the surface of the spherical body. Again, it .not infrequently happens that the relation between the sphere-body and the walls of the dies is such that as the various surfaces come into contact, there is formed an air-cushion that prevents totality of contact, and which will be removed by the use of the ducts, and also to allow, if desired, the introduction of additional grinding substance; The radial disposition of the ducts 19, will result in a decrease of resistance in the expulsion of the discarding materials. Each depression 15 may have strips of emery-cloth or sandpa er 20 glued into it for the purpose of attac 'ng and grinding the surface of the ball 17. L

In grinding the ball 17, it is well to draw the tail-block 1 1 slightly from the headblock 7 at intervals to partly free the ball 17, and this will allow the ball to shift its position and brin a new diameter line onto the axis of revo ution. This insures that the ball 17 will be truly spherical when finished and that it will be more nearly free from circular grinding lines or scratches than it it were allowed to remain in the same position through the entire grinding process.

The foregoing bein a full, clear, and 92-,

wearer rated radially to allow the discharge of excess material in the dies as the stock-surface and the die-surfaces automatically come in contact, and means to automatically continuously urge the stock-surface and the die surfaces to complete contact.

2. A spherical-body grinding machine, comprising suitably mounted oppositely ro tatable shafts, means for supporting the same, dies carried thereby and having hemispherical depressions, said dies being perforated radially to allow the excess material in the dies to be discharged as the stocksurfaces and the die-surfaces automatically come into contact, means carried by the dies for cutting the surfaces of the-sphere, and means to automatically continuously urge the stock-surface and the die-surfaces to complete contact.

Witness my hand this 29 day of November, 1911. v

JUSEPH G. IRWIN Witnesses:

J. WxlBoosa, O. W. WESTON. 

